Short biographical sketches are given of women born before 1955 who have contributed to our knowledge on the function, structure, and molecular basis of biological photoreceptors, both energy converters and photosensors. Graphical abstract
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Research Interests: Biophysics, Chemistry, Biophysical Chemistry, Molecular Biophysics, Photobiology, and 15 moreMedicine, Biological Sciences, Photoacoustics, Intact polar lipids, Laser Flash Photolysis, CHEMICAL SCIENCES, Active site, Fourier transform infrared spectroscopy, Amino Acid Profile, Calorimetry, Halobacterium Salinarum, Detergents, Flash Photolysis, Energy Levels, and Fourier transform infrared(Medicine, Biological Sciences, Photoacoustics, Intact polar lipids, Laser Flash Photolysis, CHEMICAL SCIENCES, Active site, Fourier transform infrared spectroscopy, Amino Acid Profile, Calorimetry, Halobacterium Salinarum, Detergents, Flash Photolysis, Energy Levels, and Fourier transform infrared)
(Medicine, Biological Sciences, Photoacoustics, Intact polar lipids, Laser Flash Photolysis, CHEMICAL SCIENCES, Active site, Fourier transform infrared spectroscopy, Amino Acid Profile, Calorimetry, Halobacterium Salinarum, Detergents, Flash Photolysis, Energy Levels, and Fourier transform infrared)
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ABSTRACT Several possible origins of the complex phytochrome red to far-red light-absorbing phytochrome (Pr Pfr) phototransformation kinetics in the nanosecond-to-second time range have been examined. Heterogeneity based on protein... more
ABSTRACT Several possible origins of the complex phytochrome red to far-red light-absorbing phytochrome (Pr Pfr) phototransformation kinetics in the nanosecond-to-second time range have been examined. Heterogeneity based on protein sequence is ruled out as an origin of the multi-component kinetics because recombinant 124 kDa oat phytochrome A apoprotein reconstituted with phytochro-mobilin and the native protein are very similar in this regard throughout this time range. The Pr forms of native 124 kDa oat phytochrome A and of a homogeneous recombinant 65 kDa chromoprotein fragment exhibit thermochromic properties interpreted as arising in each case from the presence of two Pr species in thermal equilibrium. They exhibit identical photochemical properties. The complex kinetics therefore cannot result from Pr heterogeneity either. Thus, the presence of two Pr forms in equilibrium (Pr,675 and Pr,655) and the complex multiex-ponential PrPfr phototransformation kinetics observed in all time ranges are intrinsic properties of the homogeneous holoprotein of oat phytochrome A.
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Phytochrome is a photoreceptor of plants which mediates various photomorphogenic processes [1,2]. The chromophoric group of phytochrome is a covalently bound linear tetrapyrrole (phytochromobilin — PCB; Fig. 1). The photoreceptor exists... more
Phytochrome is a photoreceptor of plants which mediates various photomorphogenic processes [1,2]. The chromophoric group of phytochrome is a covalently bound linear tetrapyrrole (phytochromobilin — PCB; Fig. 1). The photoreceptor exists in two interconvertible forms, the resting state Pr and the physiologically active state Pfr. The interconversion of Pr and Pfr is initiated by photoreactions of the chromophore, followed by thermal reactions (Fig. 1). Most likely, the primary photochemical event is a Z → E double bond isomerization of one of the methine bridges (presumably ZZZ → ZZE) [2]. However, details of the molecular processes associated with the photoinduced reaction cycle are not known yet. On the other hand, such information is essential for understanding the mechanism of phytochrome’s biophysical action.
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Phytochrome is a plant photoreceptor involved in various photomorphogenic processes. The 124- kDa chromoprotein includes the linear methine- bridged tetrapyrrole phytochromobilin (POB) covalently bound to the polypeptide chain (Figure 1)... more
Phytochrome is a plant photoreceptor involved in various photomorphogenic processes. The 124- kDa chromoprotein includes the linear methine- bridged tetrapyrrole phytochromobilin (POB) covalently bound to the polypeptide chain (Figure 1) [1]. Upon light absorption phytochrome can be converted from the physiologically inactive (Pr) to the active (Pfr) form. This reversible interconversion is most likely initiated by Z/E photoisomerization at one of the methine bridges of PФB followed by yet unknown conformational changes ot the chromophore and the protein environment. In the present work we have employed near-infrared Fourier-transform resonance Raman (RR) spectroscopy to study the photoinduced reaction cycle of recombinant phytochromes from oat (Phy A) and Synecchocystes sp. SPP 6803 (Syn_Phy) reconstituted with different chromophores, i. e., PФB and phycocyanobilin (PCB) in which the vinyl substituent of ring D is reduced (Figure 1).
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One of the challenging problems in the BR cycle is the accurate determination of the photochemical quantum yield for the reaction of BR yielding its early intermediates, J and K. Due to the strong overlap between the absorption spectra of... more
One of the challenging problems in the BR cycle is the accurate determination of the photochemical quantum yield for the reaction of BR yielding its early intermediates, J and K. Due to the strong overlap between the absorption spectra of BR and K [1], it is difficult to obtain this yield through optical methods. Sub-ps LIOAS circumvents this problem by measuring the heat stored after excitation with a laser pulse, affording thus the quantum yield of the species storing the energy for a time longer than the heat integration time of the experiment.
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Biliverdin dimethylester (BVE) in ethanol and BVE incorporated into dipalmitoyl lecithine (DPL) vesicles were irradiated from 555 to 690 nm with a 15 ns tunable dye-laser pulse. A spectrum was obtained by plotting the first amplitude of... more
Biliverdin dimethylester (BVE) in ethanol and BVE incorporated into dipalmitoyl lecithine (DPL) vesicles were irradiated from 555 to 690 nm with a 15 ns tunable dye-laser pulse. A spectrum was obtained by plotting the first amplitude of the photoacoustic (PA) signal, measured with a piezoelectric detector and corrected for the different laser energies, as a function of the excitation wavelength. The system was calibrated using CuSO4 either in H2O-NH3 or incorporated into DPL-Tris buffer vesicles. The PA signal of BVE in ethanol, on one hand, showed a “defect” at ca. 640 nm with respect to the absorption spectrum. This wavelength corresponds to the fluorescence excitation maximum of BVE in ethanol. However, the magnitude of the difference between the PA and absorption spectra indicates an additional occurrence of thermally reversible photoisomerizations. On the other hand, intensity of the PA spectrum for BVE-DPL, measured over a period of 20 h, decreased with time upon incorporation of the pigment into the vesicles. The absorption spectrum, showed no such time dependence. The time behaviour of the PA signal is consistent with our previous observations of an increase in fluorescence yield with time in BVE-DPL. The PA change is, however, of a much larger magnitude. These results are interpreted in terms of a chronological decrease in the radiationless transitions of BVE upon incorporation into the more rigid lipid bilayer, and an additional increase of a photoisomerization reaction of BVE which thermally reverts to its original state.
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Abstract 8-Benzoyl-9-deuterionaphtho[de-2.3.4]bicyclo[3.2.2]nona-2,6,8-triene (12a)rearranges in a photochemical di-π-methane-type process to the l-benzoylatho[de-[2.3.4]tricyclo[4.3.0.02,9]nona-3,7-dienes 14a-c.The dihydro derivate 13a... more
Abstract 8-Benzoyl-9-deuterionaphtho[de-2.3.4]bicyclo[3.2.2]nona-2,6,8-triene (12a)rearranges in a photochemical di-π-methane-type process to the l-benzoylatho[de-[2.3.4]tricyclo[4.3.0.02,9]nona-3,7-dienes 14a-c.The dihydro derivate 13a and the hydroxypheoylmethyl analogs 21a and 22a undergo similarly regioselective rearrangements to 15a+c, 23a-c, and 24a, respectively. At 298 K the primary photoreaction directly occus from the S1(n,π*) and T2(n,π*) states, and it proceeds from T1(π,π*) and from S2(π,π*) either directly or via T2. At lower temperature on direct irradiation. S1→T intersystem crossing and triplet reaction compete with reaction from the singlet. The rearrangement 12a→14a-c proceeds along three reaction paths evolving from the two primary photochemical processes of naphthyl-vinyl and vinyl-vinyl bonding in β-position to the CO (12→25+29). Two ground-state triplet diradical intermediates such as 25 and 27 have been shown to intervene consecutively—for the first time in di-π-methane photochemistry. Each has been characterized by ESR and IR, and the second one additionally by fluorescence and fluorescence excitation, and by laser flash photolysis. The failure of products 14a-c to interconvert photochemically is ascribed to efficient energy dissipation through thermally reversible pbotocleavage of the 3-membered ring. Compounds 12 and 14 thermally interconvert in the dark which constitutes the first example of a ground-state counterpart of a di-π-methane photorearrangement. The thermal reaction includes a path with highly regioselective (and possibly concerted) product formation competing with a stepwise process causing positional scrambling. The sequence 12→14 (photochemically; Φ = 1.0 at 366 nm and 298 K) and an electrophile-catalyzed reversal 14→12 in the dark is a model of a chemical light energy storage cycle which can be conducted without loss of reactants.
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Biliverdin‐dimethylester (IIa) und sein XIIIoz‐Isomeres (IIb) werden durch Veresterung (3 verschiedene Methoden) eines Biliverdin‐Isomerengemisches (Ia)/(Ib), erhalten durch Oxidation von Bilirubin und nachfolgende chromatographische... more
Biliverdin‐dimethylester (IIa) und sein XIIIoz‐Isomeres (IIb) werden durch Veresterung (3 verschiedene Methoden) eines Biliverdin‐Isomerengemisches (Ia)/(Ib), erhalten durch Oxidation von Bilirubin und nachfolgende chromatographische Trennung, in präparativem Maßstab isoliert.
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Research Interests: Biophysics, Chemistry, Biophysical Chemistry, Molecular Biophysics, Photobiology, and 15 moreMedicine, Biological Sciences, Photoacoustics, Intact polar lipids, Laser Flash Photolysis, CHEMICAL SCIENCES, Active site, Fourier transform infrared spectroscopy, Amino Acid Profile, Calorimetry, Halobacterium Salinarum, Detergents, Flash Photolysis, Energy Levels, and Fourier transform infrared(Medicine, Biological Sciences, Photoacoustics, Intact polar lipids, Laser Flash Photolysis, CHEMICAL SCIENCES, Active site, Fourier transform infrared spectroscopy, Amino Acid Profile, Calorimetry, Halobacterium Salinarum, Detergents, Flash Photolysis, Energy Levels, and Fourier transform infrared)
(Medicine, Biological Sciences, Photoacoustics, Intact polar lipids, Laser Flash Photolysis, CHEMICAL SCIENCES, Active site, Fourier transform infrared spectroscopy, Amino Acid Profile, Calorimetry, Halobacterium Salinarum, Detergents, Flash Photolysis, Energy Levels, and Fourier transform infrared)
Research Interests: Biochemistry, Chemistry, Photochemistry, Spectroscopy, Resonance Raman Spectroscopy, and 14 moreRaman Spectroscopy, Medicine, Phytochrome, Fourier Analysis, Chemical Precipitation, Isomerization, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Protein Conformation, Overtone, Ammonium Sulfate, Biochemistry and cell biology, Molecular Structure, Medical biochemistry and metabolomics, and Avena sativa(Raman Spectroscopy, Medicine, Phytochrome, Fourier Analysis, Chemical Precipitation, Isomerization, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Protein Conformation, Overtone, Ammonium Sulfate, Biochemistry and cell biology, Molecular Structure, Medical biochemistry and metabolomics, and Avena sativa)
(Raman Spectroscopy, Medicine, Phytochrome, Fourier Analysis, Chemical Precipitation, Isomerization, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Protein Conformation, Overtone, Ammonium Sulfate, Biochemistry and cell biology, Molecular Structure, Medical biochemistry and metabolomics, and Avena sativa)
Excitation of BR with ns pulses induces a photochromic equilibrium between BR and its early intermediate K, produced in less than 5 ps [1] and living ca. 2 μs [2]. During this equilibrium the five species present (BR, BR*, J, K and K*)... more
Excitation of BR with ns pulses induces a photochromic equilibrium between BR and its early intermediate K, produced in less than 5 ps [1] and living ca. 2 μs [2]. During this equilibrium the five species present (BR, BR*, J, K and K*) relax by various processes, delivering heat to the medium. With a LIOAS experiment this heat is integrated over a time which depends on the acoustic transit time of the sound wave, τ a ′ , travelling through the laser beam cross section [3]. Although the absorption spectra of BR and K strongly overlap [1], the small differences in their absorption coefficients, e BR and e K , permit the determination of the heat evolved in the system as a function of the excitation wavelength, λ exc , and excitation energy, E exc In addition, fs-LIOAS affords the quantum yield of the primary photoreaction BR → K without the need to consider the spectral properties of the photoproduct and serves as basis for the interpretation of the ns-LIOAS data. A mathematical model describing the kinetic behavior of the species involved (Fig. 1) and the time behavior of the heat evolved was developed, similar to that in ref. [4] In contrast to the linear energy dependence found for the fs-experiments (not shown), ns-excitation yields a nonlinear dependence on E exc (Fig. 2) due to the establishment of the photoequilibrium BR ⇌ K. In order to describe the system, five differential equations are required:
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Research Interests: Chemistry, Photochemistry, Biophysical Chemistry, Medicine, Biological Sciences, and 14 morePhysical sciences, Time Resolved, Laser Flash Photolysis, CHEMICAL SCIENCES, Photothermal Therapy, Schiff Base, Amino Acid Profile, Halobacterium Salinarum, Quantum Yield, Flash Photolysis, Energy Levels, Rhodopsin, Volume change, and Rate Constant
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Abstract The dimethyl esters of biliverdin, its XIIIα isomer (mesobiliverdin) and bilirubin and the 7,13-dimethyl-2,3,8,12,17,18-hexaethyl- and 2,3-dihydrooctaethylbilitrienes form strong adducts with solvents such as tetrahydrofuran,... more
Abstract The dimethyl esters of biliverdin, its XIIIα isomer (mesobiliverdin) and bilirubin and the 7,13-dimethyl-2,3,8,12,17,18-hexaethyl- and 2,3-dihydrooctaethylbilitrienes form strong adducts with solvents such as tetrahydrofuran, acetonitrile and ethyl lactate. These are differently adsorbed on silica gel. They give rise to two peaks in high-performance liquid chromatography and are separated into two zones on preparative low-pressure column chromatography. As chromatographic methods are normally used to assess the purity of bilinoid pigments, the results represent a warning regarding the solvent systems chosen in high-performance liquid and thin-layer chromatographic analyses.
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A novel Zn()-phthalocyanine (1), peripherally substituted with four bis(N,N,N-trimethyl)amino -2-propyloxy groups prepared by chemical synthesis, is shown to be an efficient photodynamic sensitizer with a quantum yield of 0.6 for... more
A novel Zn()-phthalocyanine (1), peripherally substituted with four bis(N,N,N-trimethyl)amino -2-propyloxy groups prepared by chemical synthesis, is shown to be an efficient photodynamic sensitizer with a quantum yield of 0.6 for singlet oxygen generation in neat water, which is ...